I believe 2 mentalities are ignored or underemphasized while studying for the MCAT, and it warms my heart to see some of them brought up here. To put in my spin:
1. Have a short memory
Short memory? For the MCAT? You betcha!
Ever watch the Superbowl when a quarterback's driving his team in the middle of the 4th quarter? He's slowing chipping away at the defense and making some strides towards their goal line hoping to finalize the drive with a touchdown. His team's on the opponent's 20 yard line, a few passes at best until pay-day, when WHAM! He's intercepted and initially it's believed that all that work was for nothing. With time remaining in the quarter, how will this quarterback bounce back when he reaches the 20 yard line once again?
This is a crucial moment. You've put in all the hard work, you're on the 20 yard line, and now it's time to cash in. But in order to do so, you need to have a short memory. You can not mentally relive your mistakes while taking the test and expect to dominate it. You cannot afford to stretch your mind so thin during game time. So have a short memory. This means review your mistakes, learn from them, grow more confident knowing that you now know how to deal with whatever caused you to lose your footing in the first place, and then don't think about it! Trust yourself and your mind that the info you just reviewed will come back to you when needed. If the test is important to you then your brain will make the info a priority.
2. Treat yourself
After reading all the comments this seems to be the general advice here, and I agree. Take a break! You've got the time and you've put in the effort to reward yourself and your mind. But, please please please do not do what I see happen just way too often. Do not wake up, feel down, live the day under an emotional cloud and call it a rest day. That is what an actual wasted day looks like. But rest day/s are not wasted days at all when spent enjoying yourself! So take the time before the day starts, if you need to, to remind yourself that the rest day is a day for you and not the MCAT.
And finally as an end note: the way some questions are asked from AAMC 3 to 11 do change. There is a stronger emphasis on an analytical theme rather than fact-answered questions. Learn from this and practice. But first, treat yourself!
Cheers, and good luck!!